Golf club head processing method and golf club head

ABSTRACT

This invention provides a golf club head processing method of performing blast processing on a face surface on which a scoreline is formed. The processing method according to this invention includes the steps of filling the scoreline with a masking material before the blast processing, and removing the masking material from the scoreline after the blast processing.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to blast processing on the face surface of a golf club head.

2. Description of the Related Art

In a golf club head and, especially, in an iron type golf club head, blast processing is often performed on its face surface (for example, Japanese Patent Laid-Open Nos. 10-248974 and 10-179824). The blast processing is intended for, for example, an improvement in appearance of the face surface, reflection suppression of sunlight (glare protection), or adjustment of the back spin amount on a struck golf ball.

Unfortunately, upon blast processing on a face surface on which scorelines have already been formed, the edges and inner walls of the scorelines are also polished, and this adversely affects the accuracy of the formed scorelines. To solve this problem, Japanese Patent Laid-Open No. 10-248974 presents a proposal to perform blast processing on the face surface before scorelines are formed. In this case, however, blast processing must be performed after scorelines are formed, for the sake of convenience in terms of the manufacturing process.

SUMMARY OF THE INVENTION

It is an object of the present invention to perform blast processing on a face surface, on which scorelines have already been formed, while reducing the adverse influence that this processing exerts on the accuracy of the formed scorelines.

According to the present invention, there is provided a golf club head processing method of performing blast processing on a face surface on which a scoreline is formed, comprising the steps of: filling the scoreline with a masking material before the blast processing; and removing the masking material from the scoreline after the blast processing.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external view of a golf club head 1 according to an embodiment of the present invention;

FIGS. 2A to 2D are sectional views for explaining a method of processing the golf club head 1; and

FIGS. 3A and 3B are sectional views illustrating an example of a process of filling a scoreline 20 with a masking material 30.

DESCRIPTION OF THE EMBODIMENTS

FIG. 1 is an external view of a golf club head 1 according to one embodiment of the present invention. FIG. 1 illustrates an example in which the present invention is applied to an iron type golf club head. The present invention is suitable for an iron type golf club head and, more particularly, for middle iron, short iron, and wedge type golf club heads. More specifically, the present invention is suitable for a golf club head with a loft angle of 30° (inclusive) to 70° (inclusive) and a head weight of 240 g (inclusive) to 320 g (inclusive). However, the present invention is also applicable to wood type and utility (hybrid) type golf club heads.

The golf club head 1 has a plurality of scorelines 20 formed in its face surface (striking surface) 10. The scorelines 20 are parallel linear grooves extending in the toe-to-heel direction. Although the scorelines 20 are aligned at an equal pitch in this embodiment, they may be aligned at different pitches.

The face surface 10 is roughened by blast processing. From the viewpoint of suppressing reflection of sunlight by the face surface 10, the roughness of the face surface 10 preferably corresponds to an arithmetic average roughness of 0.5 μm (inclusive) to 4.0 μm (inclusive). Various types of blast materials (polishing materials) such as sand (sandblast) can be used for the blast processing.

A method of processing the golf club head 1, which is associated with the above-mentioned blast processing, will be described next with reference to FIGS. 2A to 2D. FIG. 2A is a sectional view of the scoreline 20 taken in a direction perpendicular to its longitudinal direction (the toe-to-heel direction) before blast processing. The scorelines 20 are formed by, for example, forging or cutting before blast processing. In this embodiment, the scorelines 20 have uniform cross-sectional shapes throughout their entire longitudinal portions except for their two ends (their toe- and heel-side ends). Also, the scorelines 20 have the same cross-sectional shape.

In this embodiment, the scoreline 20 has a pair of side walls 21 and a bottom wall 22, and has its cross-section formed in a bilaterally symmetrical trapezoidal shape. Note that the cross-sectional shape of the scoreline 20 is not limited to a trapezoidal shape, and may be another shape such as a V shape. Although rounded portions are formed on edges 23 of the scoreline 20, an arrangement in which no rounded portion is formed can also be adopted.

In the state shown in FIG. 2A, the scoreline 20 is filled with a masking material 30. FIG. 2B shows the state in which the scoreline 20 is filled with the masking material 30. A soluble solid such as a water-soluble solid or a hot-melt solid can be used as the masking material 30. An example of the water-soluble solid is a mixture of a granular substance such as salt or sand and an additive such as a water-soluble resin. Examples of the hot-melt solid are fats and fatty oils and Japanese wax and other types of waxes, and paraffin wax is especially preferable. In this embodiment, wax is assumed to be used as the masking material 30. The masking material 30 will also be referred to as the wax 30 hereinafter.

FIGS. 3A and 3B are sectional views illustrating an example of a process of filling the scoreline 20 with the masking material 30 when wax is used as the masking material 30. First, the entire face surface 10 including the scoreline 20 is coated with the melted wax 30, as shown in FIG. 3A. While the wax 30 is soft, the wax 30 on the face surface 10 is scraped with, for example, a blade 40 so that only the scoreline 20 is filled with the wax 30, as shown in FIG. 3B. After that, when the wax 30 hardens, a state shown in FIG. 2B is obtained.

In the state shown in FIG. 2B, blast processing is performed on the face surface 10. Because the scoreline 20 is filled with the masking material 30, the blast material is hindered from entering the scoreline 20, thereby suppressing roughening of the inner surfaces of the scoreline 20. In this way, blast processing can be performed on the face surface 10, on which the scorelines 20 have already been formed, while reducing the adverse effect that this processing exerts on the accuracy of the formed scoreline 20.

FIG. 2C shows the state after the blast processing. Due to the influence of the blast processing, the upper portion of the masking material 30 which fills the scoreline 20 is slightly polished and recessed. However, due to the presence of the masking material 30, the inner walls (side walls 21 and bottom wall 22) of the scoreline 20 do not roughen upon the blast processing and therefore have no traces of this processing. On the other hand, the edges 23 of the scoreline 20 sometimes have traces of the blast processing (especially in the vicinities of the boundaries between the edges 23 and the face surface 10), depending on the blast processing conditions (for example, the type of blast material and its blasting conditions) and the type of masking material 30 used in the blast processing.

After the blast processing is completed, the masking material 30 is removed from the scoreline 20. If a soluble solid is used as the masking material 30, it can be relatively simply removed by its dissolution. If wax is used as the masking material 30, as in this embodiment, it can be melted and removed by heating the face surface 10 or the entire golf club head 1. FIG. 2D shows the state after the masking material 30 is removed. With the foregoing way, the processing associated with the blast processing is completed.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2010-123203, filed May 28, 2010, which is hereby incorporated by reference herein in its entirety. 

1. A golf club head processing method of performing blast processing on a face surface on which a scoreline is formed, comprising the steps of: filling the scoreline with a masking material before the blast processing; and removing the masking material from the scoreline after the blast processing.
 2. The method according to claim 1, wherein the masking material includes wax.
 3. The method according to claim 1, wherein a roughness of the face surface after the blast processing corresponds to an arithmetic average roughness of 0.5 μm (inclusive) to 4.0 μm (inclusive).
 4. A golf club head having undergone a processing method defined in claim
 1. 5. A golf club head having undergone blast processing on a face surface thereof on which a scoreline is formed, wherein an edge of the scoreline has a trace of the blast processing, while an inner wall of the scoreline has no trace of the blast processing. 